JPS61149583A - Starting method for variable speed reversible pump-turbine or pump - Google Patents

Abstract

PURPOSE:To prevent the sudden rise of input at the time of starting and reduce a bad influence to an electric power system by opening guide vanes while raising the number of revolutions at a revolution which is lower than a steady revolution and does not cause back flow. CONSTITUTION:In starting pump, after an underwater no-discharge operating condition has been realized at the minimum starring revolution N2, the opening of guide vanes is started to open to raise the number of revolutions to N1, and guide vanes are opened to a stable starting opening GVO1. And, since the pump is in a steady stable operating condition at the time when the number of revolutions is N1 and the opening and the opening of guide vanes is in the stable starting opening GVO1, and after that the pump is shifted to a prescribed revolution N0, guide vane opening GVO0 by the ordinary speed and opening control method for the variable speed pump.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method for starting a variable speed pump-turbine or a pump, and in particular to a discharge valve or This invention relates to a method for starting a variable speed pump turbine or pump with movable guide vanes.

[Background of the invention]

Conventionally, regarding this type of device, Japanese Patent Application Laid-Open No. 56-12667
As stated in Publication No. 5, it is indicated that the efficiency of hydroelectric power generation equipment can be improved by adjusting the rotation speed, but there is no mention of a method for mitigating the impact on the power system when starting pumping operation. do not have.

Conventionally, when starting a variable-speed water pump with a movable guide vane or a pump-turbine, the horizontal axis represents time, and the vertical axis represents the opening degree, rotation speed, and input of the guide vane 7 arranged around the runner outer circumference. As shown in the conventional characteristic explanatory diagram in Fig. 3, the pump is rotated at a constant rotation speed with the guide vane closed, and although there are various specific setting conditions, basically the pump discharge pressure A method is adopted in which the guide vanes begin to open and water pumping begins when the water pressure in the upper pond exceeds the water pressure applied to the pump outlet. In figure 43,
The rotation speed remains constant from startup to steady rotation, and when the guide vanes begin to open, the pump input increases rapidly.

In Figure 4, the horizontal axis shows the flow rate, and the vertical axis shows the input and head.

In the figure, even when the guide shaft of the flow 1o is closed, the pump's manual power is only small compared to the steady input. Further, the pump input is controlled by the pumped water i1 and is not affected by the guide vane opening. Figure 4 explains that the pump input increases rapidly as the guide vane opening GVO increases as shown in Figure 3. Pv
) The points B, C, D, and E shown on each curve correspond to the points B, C, D, and E shown on the load curve in FIG.

If we start the pump at a constant rotation speed and a static head (water level difference) Ho, as is now conventionally known, then the operating point of the pump will be along the load curve from point A in the shut-off state. Guide vane opening degree GV040% from point B1 point C1 point
, 60%, and 80%, and reaches the steady operating point E of 100%. Here, the load curve is a curve that represents the relationship between head and flow rate under conditions of a constant water level and taking into account losses in the pump pipeline (waterway). ! Figure 5 shows the guide vane opening degree on the horizontal axis and the pump input on the vertical axis, and plots the changes in pump input during the startup process from point A to point E on the load curve shown in Figure 4 as high and medium. , is shown for the case of a low head, and shows that if the guide vane is opened even slightly, the pump input tends to increase rapidly.

On the other hand, in the operating range where the guide vane opening is extremely small,
The operating characteristics (water pressure pulsation and vibration of the equipment caused by it) are extremely poor, and it is undesirable to maintain this state for a long time in terms of the strength of the equipment.

Conventionally, the pump is started at a certain rotation speed.As shown in Figure 3, this startup method tends to cause the pump input to increase rapidly after pumping starts, which has a large impact on the stability of the power system. A friend who has a great influence on me. This tendency is due to the relatively large pump cut-off input as mentioned above, the insensitivity of pump manual power to the guide vane opening, and the fact that an extremely small guide vane opening is due to poor operating conditions. This is a drawback that basically cannot be resolved under the current circumstances.

FIG. 6 is a characteristic curve diagram of a variable speed pump in which the horizontal axis represents the flow rate and the vertical axis represents the human power and lift, and the envelope line is used to show the same as in the N4 diagram. In the figure, the guide vane is omitted to avoid 4I complexity, and the characteristics are expressed by an envelope that connects the characteristics at the guide vane opening that exhibits the optimum operating condition @ (maximum efficiency).

is the rotational speed in a steady operating state to obtain a predetermined flow rate Qos input Po. In addition, N1 is the rotational speed (stable starting rotational speed) at which the resuspability of the QH characteristic at this rotational speed slightly exceeds the load curve at the quiet lift Ha;
N2 is the rotation speed (
(minimum starting rotation speed).

Now, when we try to start the pump along the load curve of the head Ho, if we operate the pump at a rotation speed below Ng and open the guide vane, the hydrostatic pressure naturally exceeds the pump discharge pressure. , the pump enters the reverse region, and the pump input increases dramatically.

If the guide vane is opened during shut-off operation at the rotational speed f'lh, it is not possible to shift to the steady operating point 2 as it is, and therefore the rotational speed must be increased immediately. In this case, the operating point is point X! From point Y
The human power passes through the vicinity of the point J1 and reaches the operating point 29, and the human power reaches the point J1.

On the other hand, when shut-off operation is performed at the rotation speed N1 and the guide vane is opened, the pump reaches a stable operation point Y along the load curve from the shut-off operation point x1 even if the rotation speed is kept constant. Thereafter, operating point 2 is reached as the rotational speed increases. In this case, the pump input reaches 9 points from point J1 to point K.

Therefore, the lift height Ha in Figure 6 is also high! or start from Xo higher than the X1 point, i.e. N2 or Xs
When water pumping is started at a conventional constant rotational speed No starting from a higher constant operating rotational speed Xo, the pump input reaches the point Jo. However, as mentioned above, if pumping starts from the rotation speed N or N1, the increase speed of the pump input can be reduced. , is driven at a constant rotation speed, and is started at a high rotation speed of this constant speed. Therefore, it was impossible to avoid a sudden increase in input when starting the pump, which was detrimental to the stability of the power system.

[Purpose of the invention]

The present invention has been made in view of the above situation, and provides a method for starting a variable speed pump-turbine or a pump that can prevent the rapid rise of human power at the time of start-up and reduce the negative impact on the power system. The purpose is to

[Summary of the invention]

The method of starting the variable pump water turbine or pump of the present invention includes a discharge valve or a tilting guide vane disposed on the outer periphery of the runner, and a variable speed generator or When starting a variable speed pump turbine or pump equipped with a variable speed generator/motor,
The rotation speed of the electric motor or the generator motor at the time when the guide vane or the discharge valve starts opening,
At least the minimum rotational speed specific to the electric motor or the generator motor, the rotational speed that does not reach the backflow region of the pump-turbine or the pump, and the minimum rotational speed that can be controlled by a speed control device, and as the opening degree of the guide vane increases, the rotational speed Loll in a way that increases the number. In other words, the pump input is proportional to the cube of the rotation speed, and the lower the rotation speed, the smaller the pump input, and the number of times that water can be pumped without increasing flow after shut-off operation is in a steady stable operation state. Considering that the rotation speed is lower than the steady rotation speed, the method is to perform underwater closed-off operation at a rotation speed that is lower than the steady rotation speed and does not cause backflow, and then opens the guide vane while increasing the rotation speed. .

[Embodiments of the invention]

EMBODIMENT OF THE INVENTION Hereinafter, a method of starting the pump of the variable speed pump-turbine 1& of the present invention will be explained with reference to FIG. 1 using an embodiment.

FIG. 1 is a block diagram of the starting system. In the figure, 1
is a pump input setting device, 2 is a water level difference detector, 3 is an appropriate rotation speed and guide vane opening setting device, 4 is a Fi minimum starting rotation speed setting device, 5 is a speed and opening control device that is specific to the motor or generator motor 8 It is designed to be controlled at or above the minimum rotational speed. 6Fi is a rotation speed detector, and 7 is an opening degree detector. Further, 9 is a pump or a pump water wheel, and 10 is a stable starting rotation speed setting device.

In the case of conventional startup, from the pump manual power P set from, for example, a numerical value of surplus power by the pump input setting device 1 and the quiet head He detected by the water level difference detector 2,
The optimum rotational speed No. and the optimum guide vane opening degree G V Oo in the steady operating state are set by the appropriate rotational speed and appropriate guide vane opening degree setting device 3 and manually inputted to the speed and opening degree control device 15 . The speed and opening degree control device 5 controls the rotation speed and the guide vane opening degree to N while receiving feedback of the actual rotation aN and the guide vane opening degree GVO.

Optimal values of each rotation speed and guide vane opening G
It is controlled to V Oo and started at a constant high rotation speed.

In contrast, in this embodiment, a minimum starting rotation speed setting device 4 and a stable starting rotation speed setting device 10 are added, which are shown within the dotted lines. From the output signal of the water level difference detector 2, the minimum starting rotation speed N that does not cause backflow is determined by the minimum starting rotation speed setting device 4 and manually inputted to the speed and opening control device 11i5. At the same time, from the output signal of the water level difference detector 2, the rotation speed N1 (stable starting rotation speed) and the rotation speed aNt O when the pump is turned on and open [GVOt
(Stable starting opening degree) is determined by the stable starting rotation speed setting device IO and inputted to the speed and opening degree control device 5.

Compared to the case where the vane opening degree ovoo is input, in this embodiment, the minimum starting rotation speed N2, the stable layer/auxiliary rotation speed N1, and the stable starting guide vane opening degree G V O+ at the rotation speed N1 are input. This is what is input.

In Figure 2, time is plotted on the horizontal axis, and guide vane opening is plotted on the vertical axis.
The characteristic diagram of this embodiment is shown by taking the rotation speed and pump input, and the pump input shown by the dotted line is the conventional rotation speed N.
This is the case when started with o.

When starting the pump, after realizing the underwater shut-off operation state at the minimum starting rotation speed N2, the guide vane opening degree is increased from 0 to the rotation speed NK at the rotation speed NI, and the guide vane is maintained at a stable starting opening degree. Open to G V 01. still,
In this case, the number of rotations is N! is the minimum control speed provided in the speed and opening control device 5, and
The numerical value is determined by the minimum rotational speed determined for each L electric motor, for example, the rotational speed Ns shown in FIG. 2. JN3 is at the illustrated position t'iNt・N in Figure 2.
Although the case where Ns and Nz are higher than 3 is shown, it is also possible that they are lower than Ns and Nz. When the rotation is aN+ and the guide vane steady starting opening degree ovot, the pump shifts to the steady and stable operation guide vane opening degree G V Oo K . Therefore, the pump can be started with a lower pump input than the conventional pump shown by the dotted line in FIG.

As described above, the method for starting a variable speed pump turbine or pump of this embodiment is to adjust the rotational speed of the variable speed generator or generator motor at the time when the guide vane starts opening to the variable speed generator or the generator motor ('!). The rotation speed is set to a that is at least the minimum rotation speed specific to the motive device and that can be controlled by at least the speed control eccentricity, and that does not reach the backflow region of the pump water wheel or pump, and the guide vane opening degree is increased and the rotation speed is set as above. As a result, compared to the conventional case of starting from the rotation speed in a steady operating state, a sudden rise in the input at the time of starting can be prevented and the negative impact on the power system can be reduced.

The above example describes the case where the minimum starting rotation speed N is started from snow, but the guide vane opening is adjusted to the stable starting rotation GVOz while maintaining the rotation speed N1. It is also possible to open the opening so that the rotational speed is increased by the normal speed and opening control method as described above. However, when implemented in this manner, although the influence on the power system is greater than in the above embodiment, the influence on the power system can be reduced compared to the conventional method.

〔Effect of the invention〕

As described above, the method for starting a variable speed pump-turbine or pump according to the present invention has the effect of preventing a sudden rise in input at the time of start-up and reducing the negative impact on the power system.

[Brief explanation of the drawing]

Figure 41 is a block diagram of a starting system of a variable speed pump-turbine or a device implementing the pump starting method of the present invention, l1g.
Figure 2 is a characteristic diagram of the guide vane opening, rotation speed, and pump input at the time of starting the Mi device in Figure 41, and the third figure is the guide vane opening at the time of starting the conventional variable speed pump-turbine or pump.
A characteristic diagram of the rotation speed and pump input. Figure 4 is a characteristic curve diagram of the conventional pump at a steady rotation speed. Figure 5 is an explanatory diagram of the change in pump input depending on the guide vane opening degree at a steady rotation speed of the pump shown in Figure 4. , 86 is a characteristic curve diagram of a conventional variable speed pump shown by an envelope line. 21... Pump input setting device, 2... Water level difference detector, 4... Minimum starting rotation speed setting device, 5 ...Speed and opening control device, ...4 motors or power generators, 9...pumps (and 1 other person)'' Figure 3

Claims (1)

[Claims] 1. A variable speed pump water turbine or pump equipped with a movable guide vane arranged around the outer periphery of the discharge valve or runner, and a variable speed electric motor or variable speed generator motor that is connected in parallel to the power system and rotates the runner. In the starting method, the rotational speed of the electric motor or the generator motor at the time when the guide vane or the discharge valve starts opening is determined to be at least the minimum rotational speed unique to the electric motor or the generator motor and the rotational speed of the pump water turbine or the pump. A method for starting a variable speed pump-turbine or a pump, characterized in that the rotation speed does not reach a backflow region and the minimum rotation speed that can be controlled by a speed control device, and the rotation speed is increased while increasing the opening degree of the guide vane.